Temporary maintenance enclosures and methods of maintaining turbine blades

ABSTRACT

A temporary maintenance enclosure for the maintenance of at least part of a turbine blade, said enclosure comprises a number of side walls which substantially surround the circumference of a blade in need of maintenance; and a roof extending from said side walls towards said blade; wherein said roof comprises an aperture through which said blade is received.

FIELD OF THE INVENTION

The invention relates to temporary maintenance enclosures for themaintenance and repair of tall structures, and in particular for themaintenance of wind turbine blades.

BACKGROUND TO THE INVENTION

Swift deployment of equipment for the maintenance of wind turbines isever more important as increasingly this renewal power source is reliedupon by large populations.

Maintenance and repair of tall structures, such as wind turbines, istypically conducted using cranes, rigid suspension structures or byrelying on pre-existing platforms for maintenance to be carried out.Another alternative is for individuals to scale these structures withthe aid of harnesses and ropes to carry out maintenance and repair workwithout the use of heavy machinery or maintenance apparatus.

The following prior art documents are acknowledged: DE102010011365,DE202009002054, US2011/0167633, DE10118906 and DE19909698.

However, the use of cranes and rigid suspension structures isinefficient as this heavy machinery cannot be straightforwardly andquickly transported between structures in need of maintenance. Theproduction and use of these machines is costly, and a furtherdisadvantage is their own need for expensive and time consuming repair.

Reliance on pre-existing platforms carries the disadvantage that oftenthese are not adjustable and therefore the work that can be carried outfrom the platform is limited. They are also costly to produce andtherefore an alternative which can be cost effectively and speedilydeployed is required.

The amount of maintenance work is also limited where individuals useharnesses to scale these large structures. As well as the obvious safetyconsiderations, it is also an inefficient exercise as it takes engineersa considerable time to move around a structure and often they will notbe able to take all the required equipment in a single trip.

A further disadvantage with current apparatus is that poor weatherconditions can limit the extent to which work can be carried out on aturbine. Heavy wind, cold temperatures, adverse humidity and/or rain canprevent the deployment of these apparatus as, without adequateprotection, the repair equipment and section of the turbine to bemaintained could be compromised. Maintenance work of a wind turbineblade is also problematic where the ambient temperature of the blade istoo low.

The object of the invention is to therefore alleviate at least theseproblems.

SUMMARY OF THE INVENTION

In a first broad independent aspect, the invention provides a temporarymaintenance enclosure for the maintenance of at least part of a turbineblade, said enclosure comprising a number of side walls whichsubstantially surround the circumference of a blade in need ofmaintenance; and a roof extending from said side walls towards saidblade; wherein said roof comprises an aperture through which said bladeis received.

This configuration provides the advantage of an enclosure wheremaintenance of a turbine blade can be carried out in poor weatherconditions. This improves the safety of maintenance operations andallows time and cost efficient maintenance of a large number of turbineblades.

Preferably, said enclosure is at least partially inflatable. Thisconfiguration provides the advantage of a maintenance structure, whichis quick and straightforward to deploy. This way, maintenance/repairwork can be swiftly carried out. This configuration also minimises theweight of the enclosure so that it may be easily transported and so thatit may cause minimal strain to the turbine when suspended.

Preferably, said roof is inflatable. This configuration provides theadvantage of surrounding the circumference of a blade to be maintainedwithout applying excess force against the blade. It also minimises theweight of the enclosure.

Preferably, said side walls are collapsible. This configuration providesthe advantage of minimising the size of the enclosure when it is notdeployed in order to straightforwardly store and transport the enclosurewhen not in use.

Preferably, said roof incorporates an inflatable portion, a seal aboutsaid aperture and a flexible sheath extending from said aperture to saidinflatable portion. This configuration prevents water from entering theenclosure, and therefore from damaging the blade during repair, when theenclosure is deployed about a turbine blade. It also allows theenclosure to move up and down the blade whilst preventing water entry,i.e. allowing the enclosure to move without requiring an operator todetach and reattach the enclosure to the blade whilst repair work takesplace.

Preferably, said enclosure comprises a platform located inside said sidewalls. This configuration allows maintenance and repair work to becarried out straightforwardly when the enclosure is suspended above theground.

Preferably, said enclosure is adapted to fit around a platform. Thisconfiguration allows the enclosure to be attached to a separatepre-existing platform, similar to those that are already used. Thisconfiguration also allows maintenance and repair work to be carried outstraightforwardly when the enclosure is suspended above the ground.

Preferably, said seal incorporates a member defining said aperture. Thisconfiguration provides the advantage of effectively sealing to a turbineblade to prevent water entry whilst preventing damaging load from beingapplied to the blade.

Preferably, said member is inflatable. This configuration isparticularly advantageous because the inflatable member reduces the riskof damage to the blade.

Preferably, said enclosure further comprises suspension means forsuspending said enclosure in position relative to said blade. Thisconfiguration provides the advantage of being able to lift the enclosureto an above ground level position so that maintenance work can becarried out on a turbine blade. This configuration also allows theenclosure to be vertically moveable in order for it to be positionedoptimally for maintenance work.

Preferably, said side walls and said roof comprise a plurality ofinflatable compartments. This configuration provides the advantage ofincreasing the strength of the enclosure. It also improves the safety ofthe enclosure because, if a compartment becomes deflated, the overallintegrity of the enclosure is maintained.

Preferably, said inflatable compartments have a tubular configuration.This configuration provides the advantage of further increasing thestrength of the enclosure.

Preferably, said platform incorporates a barrier, and said barrier iscollapsible. This configuration provides the advantage of minimising thesize of the enclosure when not in use. When in use, the barrier reducesthe risk of harm to operators as they are kept at a safe distance fromthe blade and, if present, from an aperture on the platform.

In a second broad independent aspect, the invention provides a method ofmaintaining a turbine blade, comprising the steps of:

-   -   providing a platform on which maintenance of a turbine blade can        occur;    -   deploying a temporary maintenance enclosure which is adapted to        fit around said platform; said enclosure comprising a number of        side walls which substantially surround the circumference of a        blade; and a roof extending from said side walls towards said        blade;    -   preferably Inflating an inflatable portion of said roof; and    -   preferably securing a flexible sheath, which extends from the        aperture in said roof, to said turbine blade.

This method provides the advantage of carrying out maintenance work on aturbine blade even where there are poor weather conditions. This methodimproves the safety of maintenance operations and allows time and costefficient maintenance of a large number of turbine blades.

Preferably, said method comprises the step of raising said enclosureprior to securing said flexible sheath to said blade. This step providesthe advantage of allowing the flexible sheath to be secured to a turbineblade prior to conducting maintenance work.

Preferably, said method comprises the step of lowering said enclosuresubsequent to securing said flexible sheath to said blade. This stepprovides the advantage of positioning the enclosure at its' location ofmaintenance whilst the flexible sheath provides protection from waterentry.

Preferably, said method comprises the step of at least partiallyinflating said enclosure. This step provides the advantage of minimisingthe weight of the enclosure so that strain on the turbine is minimisedwhilst the enclosure is suspended. It also minimises the overall size ofthe enclosure when it is not deployed so that it can bestraightforwardly transported and stored.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 shows a perspective view of a preferred embodiment of theinvention.

FIG. 2 shows another perspective view of a preferred embodiment of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

The temporary maintenance enclosure of the current invention is shown inFIG. 1, referenced generally as 10. Maintenance of the wind turbine 14includes, but not exclusively: repairing, cleaning, inspecting,installing retrofit parts, painting of the turbine and the replacementof parts.

In a preferred embodiment of the invention, the temporary maintenanceenclosure 10 comprises a number of side walls, such as 11, 12, 17 and18. The side walls substantially surround the circumference of a blade13 of a wind turbine 14. The enclosure 10 also comprises a roof 15 whichextends from the side walls to the blade 13. The roof 15 comprises anaperture 16 through which, in use, the blade 13 is received.

In the preferred embodiment the enclosure comprises four side walls, 11,12, 17 and 18, which form a square and/or rectangle configuration aroundthe blade 13. However, any number of side walls could be used to thesame effect.

In this preferred embodiment, the enclosure also comprises a platform21, which is located within the side walls 11, 12, 17 and 18. Theplatform comprises four flanks, which are attached to the four sidewalls which form an aperture 25 so that the enclosure can receive theblade and move up and down the blade freely to conduct maintenance work.

In a preferred embodiment, the enclosure 10 is at least partiallyinflatable. This allows fast deployment of the enclosure as it can bestraightforwardly transported to a desired location and swiftly inflatedso it is suitable for use. This configuration also minimises the weightof the enclosure so that strain on the turbine is minimised.

FIG. 2 shows another perspective view of the preferred embodiment of theenclosure. In this preferred embodiment, the platform 21 is bounded byeach of the side walls, 11, 12, 17 and 18, which extend below andsupport the platform so that the platform is securely held as part ofthe enclosure. In this configuration the platform provides furtherstrength to the enclosure and allows operators to effectively movearound and maintain the blade.

In the preferred embodiment, the platform incorporates a barrier forminimising the risk of harm to operators. The barrier is located alongthe inner edge of each flank of the platform to prevent operators fromfalling through the aperture of the platform, between the platform andthe blade. Preferably, the barrier is collapsible so that when it is notin use, the size of the enclosure is minimised. Alternatively, thebarrier is removeably attached to the platform so that the barrier canbe inserted/removed prior to and following inflation and deflation ofthe enclosure.

In the preferred embodiment of the invention, the platform consists of anon-inflatable robust material capable of holding the weight ofoperators and/or repair equipment. However, it is envisaged that theplatform could consist of an inflatable material which is capable ofholding the weight, which could therefore further minimise the size ofthe enclosure when not in use and minimise the strain applied to theturbine when the enclosure is deployed.

In an alternative embodiment the enclosure 10 is adapted to fit around aplatform. This allows the enclosure to be used with existing platformsto provide them with the advantages already discussed.

In an alternative embodiment the roof 15 is inflatable. This provides asnug connection between the enclosure 10 and the blade 13 in order tominimise or preferably prevent the entry of water into the enclosure,thereby minimising the risk of damage to the blade or maintenanceequipment. In this embodiment the side walls, such as 11 and 12, arecollapsible in order to minimise the size of the enclosure 10 when notin use.

Preferably, the enclosure is comprised substantially of transparentand/or non-transparent plastics material, however it is envisaged thatthe enclosure could consist of any light and robust material which ispreferably capable of being inflated.

In the preferred embodiment, the roof 15 incorporates an inflatableportion and a seal about the aperture 16. The roof 15 also incorporatesa flexible sheath 19 which, extends from the aperture 16 of the roofonto the blade 13. The flexible sheath 19 consists of a waterproofmaterial, preferably of flexible plastics material, which prevents waterfrom entering the enclosure by surrounding the circumference of theblade 13. This allows the enclosure to move up and down a blade withoutthe requirement for an operator to detach and reattach the enclosure asit moves. In an alternative embodiment the flexible sheath 19 furtherincorporates an inflatable portion, such as 20 which, in use, isinflated to form a watertight connection with the blade 13. In anotheralternative embodiment the flexible sheath 19 incorporates anon-inflatable seal which is tightened around the blade 13.

In the preferred embodiment, the sheath incorporates a seal at theaperture 16 of the enclosure or where the sheath 19 is attached to theblade 20. This provides the advantage of effectively sealing theenclosure 10 to the turbine blade 13 in order to prevent water entry,whilst preventing damaging load from being applied to the blade.

In the preferred embodiment, the enclosure further comprises suspensionmeans 22 to suspend the enclosure 10 from the wind turbine 14 whilstmaintenance work is conducted. In this embodiment the suspension meanscomprises a tether, which is attached to the wind turbine 14 and theenclosure 10 so that the enclosure can move in a vertical direction inrelation to the turbine 14. This allows the enclosure 10, with itsaperture 16 to surround the circumference of a blade 13 in order formaintenance work to be carried out.

In an alternative embodiment, the enclosure is raised by means of aground level elevation system. This applies minimal strain on theturbine when maintenance is conducted on the blade. In anotheralternative embodiment, the enclosure further comprises a hydraulicsystem, positioned on the platform, for elevating and lowering theenclosure.

In the preferred embodiment, the side walls and roof comprises a numberof inflatable compartments, such as 23 and 24, which have a tubulararrangement. The tubular configuration of the compartments increases thestrength of the enclosure 10 so that it is more resistant against poorweather conditions such as heavy wind and rain. The tubularconfiguration also assists in maintaining the overall shape of theenclosure when inflated and when deflated.

In an alternative embodiment, the roof 15 of the enclosure 10incorporates an inflatable seal which is located at the aperture, ratherthan a flexible sheath, to provide a water tight connection with theblade.

In use, in the preferred embodiment of the invention, the enclosure 10can be straightforwardly stored and then transported to a turbine inneed of maintenance when required. Once at the turbine the enclosure 10can be deployed. This may involve attaching the enclosure to a separatepre-existing platform or, preferably, deploying an enclosure which hasan integral platform. Once deployed, the enclosure can be attached tothe turbine via the suspension means and hoisted to a required positionwhereby the enclosure surrounds a section of a blade of a turbine.

Prior to being positioned at the maintenance position, the enclosure maybe raised above the maintenance position in order to attach the flexiblesheath to the blade. Following this the enclosure can be subsequentlylowered to the required maintenance position. The flexible sheath ispreferably attached to the blade via a belt-style connection, whichallows the sheath to be tightened around the blade in a controlledmanner so that the blade is not damaged.

Once maintenance of the blade has been completed the enclosure can belowered towards the ground. Prior to this, the enclosure is raised againto the height of the top of the flexible sheath in order to detach thesheath from the blade. However, in an alternative embodiment, means arepresent for remotely detaching the sheath from the blade.

Once the enclosure has been lowered to ground level, the suspensionmeans can be detached from the turbine and the enclosure can be deflatedor collapsed. If the platform incorporates a barrier, this can also becollapsed in order to minimise the size of the enclosure when not inuse. If the enclosure has been attached to a separate platform, this canbe detached before the enclosure is removed.

The invention claimed is:
 1. A temporary maintenance enclosure for themaintenance of at least part of a turbine blade, said enclosurecomprising a number of side walls which substantially surround thecircumference of a blade in need of maintenance; and a roof extendingfrom said side walls towards said blade; wherein said roof comprises anaperture through which said blade is received; wherein said enclosurecomprises a platform which is bounded by each of said side walls; andwherein said roof incorporates an inflatable portion, a seal about saidaperture and a flexible sheath extending from said aperture to saidinflatable portion.
 2. A temporary maintenance enclosure according toclaim 1, wherein said enclosure is at least partially inflatable.
 3. Atemporary maintenance enclosure according to claim 1, wherein said roofis inflatable.
 4. A temporary maintenance enclosure according to claim1, wherein said side walls are collapsible.
 5. A temporary maintenanceenclosure according to claim 1, wherein said seal incorporates a memberdefining said aperture.
 6. A temporary maintenance enclosure accordingto claim 5, wherein said member is inflatable.
 7. A temporarymaintenance enclosure according to claim 1, wherein said enclosurefurther comprises suspension means for suspending said enclosure inposition relative to said blade.
 8. A temporary maintenance enclosureaccording to claim 1, wherein said side walls and said roof comprise aplurality of inflatable compartments.
 9. A temporary maintenanceenclosure according to claim 8, wherein said inflatable compartmentshave a tubular configuration.
 10. A temporary maintenance enclosure forthe maintenance of at least part of a turbine blade, said enclosurecomprising a number of side walls which substantially surround thecircumference of a blade in need of maintenance; and a roof extendingfrom said side walls towards said blade; wherein said roof comprises anaperture through which said blade is received; and wherein saidenclosure comprises a platform which is bounded by each of said sidewalls, wherein said platform incorporates a barrier, and said barrier iscollapsible.
 11. A method of maintaining a turbine blade, comprising thesteps of: a. providing a platform on which maintenance of a turbineblade can occur; b. deploying a temporary maintenance enclosure which isadapted to fit around said platform; said enclosure comprising a numberof side walls which bound said platform and substantially surround thecircumference of a blade; and a roof extending from said side wallstowards said blade; said roof comprising an aperture through which saidblade is received; c. securing a flexible sheath, which extends from theaperture in said roof, to said turbine blade.
 12. A method according toclaim 11, comprising the step of inflating an inflatable portion of saidroof.
 13. A method according to claim 11, comprising the step of raisingsaid enclosure prior to securing said flexible sheath to said blade. 14.A method according to claim 11, comprising the step of lowering saidenclosure subsequent to securing said flexible sheath to said blade. 15.A method according to claim 11, comprising the step of at leastpartially inflating said enclosure.
 16. A temporary maintenanceenclosure for the maintenance of at least part of a turbine blade, saidenclosure comprising a number of side walls which substantially surroundthe circumference of a blade in need of maintenance; and a roofextending from said side walls towards said blade; wherein said roofcomprises an aperture through which said blade is received; and a sheathwhich extends between said aperture and said blade; wherein the sheathincorporates a seal where the sheath is attached to said blade; andwherein said enclosure is at least partially inflatable.